Methods and compositions for producing double allele knock outs
The present invention provides a method and compositions utilizing the CRISPR system to disrupt a target gene in eukaryotic cells to produce double allele knock outs. The method finds use in producing afucosylated antibodies with enhanced ADCC activity.
1. A method of producing a double allele knock-out of a target gene in a eukaryotic cell, comprising the steps of: providing the cells with a CRISPR system comprising a Cas9 nuclease, wherein the Cas9 nuclease has two functional nuclease domains that produce a double-stranded break, and three to seven targeting RNAs located in the same gene, wherein each targeting RNA is comprised of a crRNA and a tracrRNA, wherein each crRNA has a different sequence, and expressing the CRISPR nuclease and the targeting RNAs whereby the target gene is knocked out in both alleles of the cell.
2. The method of claim 1 , wherein the CRISPR system comprises three targeting RNAs.
3. The method of claim 2 , wherein each targeting RNA has the same tracrRNA.
4. The method of claim 2 , wherein at least two targeting RNAs are complementary to a corresponding target sequence in the targeted gene, and wherein the target sequences are located in a contiguous stretch of 375 bp, 200 bp, or 150 bp in the target gene.
5. The method of claim 1 , wherein said cells are mammalian.
6. The method of claim 5 , wherein said cells are CHO cells, 293 cells, NSO cells, embryonic stem cells, or derivatives thereof, or antibody-producing cells or derivatives thereof.
7. The method of claim 1 , wherein the tracrRNA and the crRNA are connected by a hairpin RNA linkage.
8. The method of claim 1 , wherein at least two targeting RNAs are complementary to a corresponding target sequence in the targeted gene, and wherein the target sequences are in a single exon of the targeted gene.
9. The method of claim 1 , further comprising the step of providing the eukaryotic cells with a nucleic acid construct comprising a polynucleotide encoding an antibody and a control region operably linked to the polynucleotide encoding the polypeptide.
10. The method of claim 9 , further comprising the step of expressing the antibody from the nucleic acid construct in the eukaryotic cell.
11. The method of claim 1 , wherein the targeted gene is a fucosyltransferase.
12. The method of claim 1 , wherein the targeted gene is glutamine synthetase.
13. The method of claim 1 , wherein the targeted gene is dihydrofolate reductase (DHFR).
14. The method of claim 1 , wherein the targeted gene is a sialidase.
15. The method of claim 1 , further comprising the step of growing the eukaryotic cell that has the target gene knocked out in both alleles of the eukaryotic cell.
16. A method of producing a double allele knock-out of a target gene in a eukaryotic cell, comprising the steps of: providing the cells with a CRISPR system comprising a Cas9 nuclease, wherein the Cas9 nuclease has two functional nuclease domains that produce a double-stranded break, and three to seven targeting RNAs located in the same gene, wherein each targeting RNA is comprised of a crRNA and a tracrRNA, wherein each crRNA has a different sequence, expressing the CRISPR nuclease and the targeting RNAs whereby the target gene is knocked out in both alleles of the cell, and losing the CRISPR system from the eukaryotic cell.
17. The method of claim 16 , further comprising the step of growing the eukaryotic cell that has the target gene knocked out in both alleles of the eukaryotic cell.
18. The method of claim 17 , further comprising the step of providing the eukaryotic cells with a nucleic acid construct comprising a polynucleotide encoding an antibody and a control region operably linked to the polynucleotide encoding the polypeptide.
19. The method of claim 18 , further comprising the step of expressing the antibody from the nucleic acid construct in the eukaryotic cell.